Aegir,
I didn't realize that you were such a simpleton. Apparently you need a road map.
As I said before wether you are diving dry or wet, what type of tanks are being used and what type of backplate DOES MATTER. If you have a Steel pony or SS backplate on then there is that 6 pounds of weight that you will not have on your weight belt. Will this leave you with enough weight to ditch if needed? To have a balanced rig, you may well need to have included at least 20 pounds of ditchable weight, assuming you can swim up with a negative 10 pounds buoyancy. And with a steel pony or SS backplate adding non-ditchable weight, this is not too easy. It's an awful lot easier with an aluminum tank or backplate so the six pounds can be replaced with ditchable weight. Otherwise you're whole rig simply gets heavier. This same logic can be applied to all equipment as well.
P.S.
If you need 42 pounds of lift you will need to displace an appropriate amount of water. In this case about 2/3 of a cubic foot (since 1 cubic foot of water is 61.4 pounds). Get an appropriate sized wing.